1. Field of the Invention
The present invention relates to an information transceiver system, and in particular to an information transmission device or an information reception device in an information transceiver system for transmitting/receiving specific information.
Recently, owing to developments of communication technologies, various forms by which the information transceiver system transmits/receives information such as cells, packets and frames have been reduced to practice.
In such an information transceiver system, it is important to limit information to be transmitted/received within a specific group or to prevent the information from being recognized by others depending on an importance of the information.
2. Description of the Related Art
FIG. 16 shows an ATM-PON (Asynchronous Transfer Mode Passive Optical Networks) system that is one arrangement of an information transceiver system. This network system is composed of an Optical Line Terminator (hereinafter, abbreviated as OLT) 10, an optical coupler 30 connected to the OLT 10, and Optical Network Units (hereinafter, abbreviated as ONU""s) 20_1-20_n (hereinafter, occasionally represented by a reference numeral 20; n=64 at the maximum) connected to the optical coupler 30.
In the ATM-PON system, a transmission of information is performed by cells. The OLT 10 transmits a down cell 41 to the ONU""s 20 which respectively receive the same down cell 41 through the optical coupler 30. The ONU""s 20 respectively transmit up cells 42_1-42_n to the OLT 10 through the optical coupler 30. After going through the optical coupler 30, the up cells 42_1-42_n are transmitted to the OLT 10 in time sequence.
G.983 that is ITU-T recommendation is set up in the ATM-PON system. The down cell 41 and the up cell 42 respectively have two types of cells, a user cell and a Physical Layer Operation And Maintenance Cell (hereinafter, abbreviated as PLOAM cell) for management.
The PLOAM cell is periodically multiplexed into a user cell to be transmitted, so that manager information is exchanged between the OLT 10 and the ONU""s 20 by using a message field of the PLOAM cell.
The G.983 prescribes the usage of the message field, that is a message called a vendor specific message. A detailed usage of the vendor specific message is not prescribed in the G.983, so that the vendor specific message is permitted to be freely used per vendor.
FIG. 17 shows a format of a down PLOAM cell. This cell is composed of 53 octets, i.e. 5 octets of octet Nos. xe2x80x9c1xe2x80x9d-xe2x80x9c5xe2x80x9d for a header field 45 and 48 octets of octet Nos. xe2x80x9c6xe2x80x9d-xe2x80x9c53xe2x80x9d for a payload field 46. The header field 45 includes a 12-bit Virtual Path Identifier (hereinafter, abbreviated as VPI) field, a 16-bit Virtual Channel Identifier (hereinafter, abbreviated as VCI) field, and a 3-bit Payload Type (hereinafter, abbreviated as PT) field.
Destination addresses of cells are indicated in the VPI and VCI fields, and the type of cells such as a user cell or an OAM cell is indicated in the PT field. When the highest bit is xe2x80x9c1xe2x80x9d in the PT field, it is indicated that the cell is the PLOAM cell. When the highest bit is xe2x80x9c0xe2x80x9d, it is indicated that the cell is the user cell. It is to be noted that a user network interface has the VPI field only for the lower 8 bits, and a GFC field for the higher 4 bits.
A vendor specific message field 50 is composed of 13 octets of octet Nos. xe2x80x9c40xe2x80x9d-xe2x80x9c52xe2x80x9d in the payload field 46. The Nos. xe2x80x9c40xe2x80x9d and xe2x80x9c41xe2x80x9d are respectively a PON-ID (Passive Optical Network Identifier) field 51 and a message ID field 52. The octet Nos. xe2x80x9c42xe2x80x9d-xe2x80x9c51xe2x80x9d and xe2x80x9c52xe2x80x9d are respectively a message field 53 and a CRC calculation result field 54.
The PON-ID field 51 is a field for designating an ONU which receives a message. When all of the ONU""s are designated, xe2x80x9c01000000xe2x80x9d is set. When the ONU""s are individually designated, a designating PON-ID is set.
The message ID field 52 is a field for indicating a type of a message. When the value thereof is xe2x80x9c01111XXXxe2x80x9d, it indicates a vendor specific message.
The vendor specific message may be used for so-called SWDL (SoftWare DownLoad) or the like where the OLT 10 supplies a necessary software to the ONU""s 20. However, when the message field in plain text, not ciphered is transmitted as it is, there is a possibility that the contents of the message is disclosed to the ONU""s 20 other than the destination ONU.
However, in the G.983, the method of ciphering the message field of the vendor specific message has not been prescribed.
Also, in the G.983, broadcasting of a vendor specific message in which specific ONU""s 20 are regarded as forming a single group has not been prescribed. Namely, it has been impossible to perform the ciphering and the broadcasting of the message field.
On the other hand, broadcasting the user cell can be applied to all ONU""s 20 such as a cable TV. However, there is a possibility that the user cell in plain text is received by the ONU""s 20 other than the destination ONU.
However, in the G.983, while the ciphering method of the user cell is prescribed by churning/dechurning as a usual key for the case the OLT 10 and the ONU 20 are in a one-to-one relationship, the method is not prescribed for the case the OLT and the ONU are in a one-to-many relationship. Namely, it has been impossible to perform a broadcast ciphering of the user cell.
This will be specifically described referring to FIGS. 18A-18E.
FIGS. 18A-18E show an operation example of the ATM-PON system shown in FIG.16. This example especially shows a case where a PLOAM cell 44 in the down cell 41 is transmitted from the OLT 10 to the ONU""s 20_1-20_4. Each ONU 20 has its own identifier, the PON-ID.
FIG. 18A shows PLOAM cells 44_1-44_4 (hereinafter, represented by a reference numeral 44) transmitted by the OLT 10. FIGS. 18B-18E show the PLOAM cells 44_1-44_4 respectively received by the ONU""s 20_1-20_4.
Both of the ONU""s 20_1 and 20_2 are devices made by a vendor company A, and their vendor ID is xe2x80x9cAxe2x80x9d. The ONU""s 20_3 and 20_4 are devices respectively made by a vendor company B and a vendor company C, and their vendor ID""s are xe2x80x9cBxe2x80x9d and xe2x80x9cCxe2x80x9d.
When transmitting a vendor specific message to the ONU 20_1 in FIG. 18A, the OLT 10 sets the PON-ID of the ONU 20_1 in the PON-ID field 51 (see FIG. 17), and transmits the PLOAM cell 44_1 in which a predetermined message is inserted into the message field 53.
In FIG. 18B, the ONU 20_1 receives the PLOAM cell 44_1, and receives the message since the PON-ID of the PON-ID field 51 in the PLOAM cell matches its own PON-ID.
In FIGS. 18C-18E, each of the ONU""s 20_2-20_4 respectively receives the PLOAM cell 44_1, but does not receive the message since the PON-ID set in the PON-ID field 51 does not match its own PON-ID.
When transmitting the vendor specific message to the ONU""s 20_1 and 20_2 that are the devices made by the same vendor company A, the OLT 10 firstly transmits the PLOAM cell 44_1 in which the PON-ID of the ONU 20_1 is set in the PON-ID field 51. The ONU 20_1 receives the message.
Furthermore, the OLT 10 transmits the PLOAM cell 44_2 in which the PON-ID of the ONU 20_2 is set in the PON-ID field 51. The ONU 20_2 receives the message.
Also, when the ONU""s 20_1-20_3 are made to form a single group and the same message is transmitted to this group, the OLT 10 sets the PON-ID""s of the respective ONU""s 20_1-20_3 in the PON-ID fields 51, and sequentially transmits the PLOAM cells 44_1-44_3 in which the same message is inserted into the message field 53. The ONU""s 20_1-20_3 respectively receive the messages from the PLOAM cells 44 in which their own PON-ID""s are set.
In FIG. 18A, when transmitting the same message to all of the ONU""s 20, the OLT 10 sets the PON-ID=xe2x80x9c01000000xe2x80x9d indicating that all of the ONU""s are designated in the PON-ID field 51, and transmits the PLOAM cell 44_4 in which the message is inserted into the message field 53. The ONU""s 20_1-20_4 receive the messages referring to the PON-ID""s.
Thus, it is possible to transmit/receive messages between a single OLT and a single ONU, and between a single OLT and all of the ONU""s. However, when specific ONU""s 20 are made to form a single group and the same message is transmitted to this group, it has been required to change the destination of the message and to send the message as many times as the number of ONU""s in the group.
Similarly, when a user cell 43 (not shown) of the same contents are transmitted to a plurality of ONU""s 20 by ciphering, it has been required to transmit the user cell as many times as the number of ONU""s in the group by churning/dechurning which is the ciphering method by the usual key of one-to-one prescribed by the G.983.
In such a prior art information transceiver system, when specific ONU""s 20 are made to form a single group and the PLOAM cell or the user cell of the message having the same contents is transmitted to the group, it has been disadvantageous that the transmission has to be repeated as many times as the number of ONU""s within the group, which results in a problem that a line capacity is suppressed and a communication time is prolonged.
It is accordingly an object of the present invention to provide an information transceiver system for transmitting/receiving specific information, wherein efficiencies of unicasting, vendor broadcasting, group broadcasting, and ciphering and deciphering them are improved.
(1) In order to achieve the above-mentioned object, an information transmission device according to the present invention comprises: a cipher message generator for generating a cipher message in which specific information is ciphered with a specific information cipher key; a key message generator for generating a key message in which the specific information cipher key is ciphered with a usual key used between its own device and a destination information reception device; and a message transmitter for transmitting the key message and the following cipher message to the destination information reception device corresponding thereto.
Namely, a key message generator generates a specific information cipher key, ciphers the specific information cipher key with a usual key used between the information transmission device itself and an information reception device, and generates a key message including the ciphered specific information cipher key. A message transmitter transmits the key message to the destination information reception device, and then transmits the ciphered message to the information reception device.
Thus, the information reception devices other than the destination information reception device can not decipher the specific information cipher key included in the received key message. Namely, the specific information cipher key is transmitted only to the destination information reception device of the key message.
(2) Also, in the above-mentioned present invention (1), in presence of a plurality of destination information reception devices, the key message generator may generate key messages in which the specific information cipher key is ciphered with usual keys used between its own device and the destination information reception devices, and the cipher message generator may generate the cipher message for the information reception devices.
Namely, in the presence of a plurality of destination information reception devices, the key message generator firstly generates a key message in which the specific information cipher key is ciphered with a usual key used between the information transmission device itself and a single destination information reception device, and the message transmitter transmits the ciphered key message to the destination information reception device.
Hereafter, the key messages in which the same specific information cipher keys as the above-mentioned cipher key ciphered with usual keys used between the information transmission device itself and remaining information reception devices are similarly generated, and the message transmitter sequentially transmits the ciphered key messages to the remaining information reception devices corresponding thereto.
Then, the cipher message generator transmits the cipher message in which the specific information is ciphered with the specific information cipher key to the information reception devices.
Thus, while the specific information is disclosed only to the information reception device having the specific information cipher key since the specific information is ciphered with the specific information cipher key, it is not disclosed to other information reception devices.
Accordingly, it becomes possible to transmit the same ciphered specific information to a plurality of information reception devices by broadcasting in a one-to-many relationship.
(3) Also, in order to achieve the above-mentioned object, an information reception device according to the present invention comprises: a key message processor for deciphering a specific information cipher key included in a received key message addressed to its own device with a usual key used between its own device and a source information transmission device; and a cipher message processor for deciphering with the specific information cipher key a cipher message following the key message and ciphered with the specific information cipher key from the source information transmission device.
Namely, a key message processor deciphers a specific information cipher key included in a key message addressed to its own device with a usual key used between the information reception device itself and an information transmission device. A cipher message processor receives a cipher message and deciphers the same with the specific information cipher key.
Thus, it becomes possible for the information reception device to receive only the specific information cipher key distributed to its own device, and to decipher the cipher message ciphered with the specific information cipher key.
It is to be noted that the cipher message may comprise a broadcast message addressed to a plurality of information reception devices.
(4) Also, in the above-mentioned present invention (1) or (2), the information transmission device may further comprise a setting message generator for generating a setting message including cipher setting information indicating whether or not the specific information is set to be ciphered with the specific information cipher key, the message transmitter may transmit the setting message and then transmit the cipher message ciphered with the specific information cipher key when the specific information is set to be ciphered, while otherwise may transmit a not-ciphered cipher message.
Namely, a setting message generator generates a setting message indicating whether or not the specific information is set to be ciphered with the specific information cipher key, and transmits the cipher message ciphered with the specific information cipher key after transmitting the setting message, when the specific information is set to be ciphered.
When the specific information is not set to be ciphered, the message transmitter transmits a cipher message not ciphered with the specific information cipher key.
Thus, when the contents of the specific information are less significant for example, it becomes possible to transmit the specific information without being ciphered with the specific information cipher key, and to omit the generation of the specific information cipher key and its transmission processing.
(5) Also, in the above-mentioned present invention (4), when the specific information is not set to be ciphered with the specific information cipher key, the message transmitter may transmit a message in which the specific information is ciphered with the usual key.
Namely, when the setting message does not indicate that the specific information is set to be ciphered with the specific information cipher key, the message transmitter transmits a message in which the specific information is ciphered with a usual key.
Thus, it is also possible to cipher the specific information with the usual key and to transmit the same.
(6) Also, in the above-mentioned present invention (2), the information transmission device may further comprise a setting message generator for generating a setting message including broadcast setting information indicating whether or not the cipher message should be transmitted by broadcasting, the message transmitter may transmit the setting message and then transmit the cipher message by broadcasting when broadcasting is set, while otherwise may transmit the cipher message addressed to the information reception devices by unicasting.
Namely, unicasting indicates a form in which an information transmission device and a reception device mutually communicate in a one-to-one relationship. Broadcasting indicates a form in which an information transmission device and a reception device mutually communicate in a one-to-many relationship. A setting message generator generates a setting message including broadcast setting information indicating whether or not the cipher message is transmitted by broadcasting, so that the message transmitter transmits the setting message.
When broadcasting is set, the message transmitter transmits the cipher message by the broadcasting addressed to all of the information reception devices. When broadcasting is not set, the message transmitter transmits the cipher message by unicasting to the information reception devices.
Thus, it becomes possible to transmit the cipher message by unicasting or broadcasting.
(7) Also, in the above-mentioned present invention (6), the setting message may further include vendor setting information for designating that the broadcasting is performed only to information reception devices made by a same vendor, and the message transmitter, after transmitting the setting message, may transmit the cipher message by vendor broadcasting when a vendor and broadcasting are set.
Namely, the setting message generator generates the setting message further including vendor setting information designating a vendor of the information reception device. When a vendor and broadcasting are set, the message transmitter, after transmitting the setting message, transmits the cipher message by broadcasting only to the information reception device made by the vendor designated by the vendor setting information.
Thus, it becomes possible to transmit the cipher message by a vendor broadcast.
(8) Also, in the above-mentioned present invention (6), the setting message may further include group setting information for designating that the broadcasting is performed only to information reception devices in a specific group, and the message transmitter, after transmitting the setting message, may transmit the cipher message by group broadcasting when a group and broadcasting are set.
Namely, the setting message generator generates the setting message further including group setting information designating a specific group of the information reception devices. When a group and broadcasting are set, the message transmitter, after transmitting the setting message, transmits the cipher message by broadcasting only to the information reception device whose group setting information belongs to a specific group.
Thus, it becomes possible to transmit the cipher message by a group broadcast.
(9) Also, in the above-mentioned present invention (3), the information reception device may further comprise a setting message processor for receiving a setting message from the source information transmission device, the setting message processor may store cipher setting information included in the setting message and indicating whether or not the specific information is set to be ciphered with the specific information cipher key, and the cipher message processor, based on the cipher setting information, may receive the cipher message after being deciphered with the specific information cipher key or without being deciphered.
Namely, a setting message processor stores the cipher setting information indicating whether or not the specific information included in the received setting message is ciphered with the specific information cipher key.
When the cipher setting information indicates that the specific information is set to be ciphered, the cipher message processor deciphers the received cipher message, with the specific information cipher key, to be received. When the cipher setting information indicates that the specific information is not set to be ciphered, the cipher message processor receives the cipher message without being deciphered.
Thus, it becomes possible to receive the specific information included in the ciphered message not ciphered with the specific information cipher key.
(10) Also, in the above-mentioned present invention (3), the information reception device may further comprise a setting message processor for receiving a setting message from the source information transmission device, the setting message processor may store broadcast setting information included in the setting message and indicating whether or not the cipher message is transmitted by broadcasting, and the cipher message processor, based on the broadcast setting information, may receive a cipher message for unicasting or broadcasting.
Namely, a setting message processor receives and stores broadcast setting information included in the received setting message and indicating whether or not the cipher message is transmitted by broadcasting.
When the broadcast setting information indicates that broadcasting is set, the cipher message processor receives a cipher message for a broadcast. When the broadcast setting information indicates that unicasting is set, the cipher message processor receives a cipher message for unicasting addressed to its own device.
Thus, it becomes possible for the information reception device to receive a cipher message for unicasting or broadcasting.
(11) Also, in the above-mentioned present invention (10), when a vendor designated by vendor setting information included in the setting message is a vendor of its own device, the setting message processor may store that the vendor of its own device is designated, and when a vendor and broadcasting are designated, the cipher message processor may receive a cipher message for vendor broadcasting addressed to its own vendor.
Namely, when vendor setting information designating its own device is included in the received setting message, the setting message processor stores that its own vendor is designated.
When the vendor of its own device and broadcasting are designated, the cipher message processor receives a cipher message for vendor broadcasting designating its own vendor.
Thus, it becomes possible for the information reception device to receive a ciphered message of vendor broadcasting.
(12) Also, in the above-mentioned present invention (10), when its own device belongs to a group designated by group setting information included in the setting message, the setting message processor may store a group ID thereof, and when a group ID and broadcasting are designated, the cipher message processor may receive a cipher message of group broadcasting of the group to which its own device belongs.
Namely, when group setting information designating its own device is included in the received setting message, the setting message processor stores a group ID thereof.
When, a group ID and broadcasting are designated, the cipher message processor receives a cipher message of group broadcasting designating the group ID to which its own device belongs.
Thus, it becomes possible for the information reception device to receive a ciphered message of group broadcasting.
(13) Also, in the above-mentioned present invention (1) or (2), the information transmission device may comprise an OLT device prescribed by ITU-T G.983.
Namely, it is possible to make an OLT device prescribed by the ITU-T G.983 corresponding to the information transmission device of the present invention.
(14) Also, in the above-mentioned present invention (3), the information reception device may comprise an ONU device prescribed by ITU-T G.983.
Namely, it is possible to make an ONU device prescribed by the ITU-T G.983 corresponding to the information reception device of the present invention.
Thus, it is possible to make the OLT device an information transmission device and to make the ONU device an information reception device in the network between the OLT device and the ONU device connected in a one-to-one or a one-to-many relationship.
(15) Also, in the above-mentioned present invention (13), the key message generator may insert the specific information cipher key into a vendor specific message of a PLOAM cell, and may cipher the specific information cipher key with the usual key to generate the key message.
Namely, after the specific information cipher key is inserted into a message field of a vendor specific message in a PLOAM cell, the key message generator ciphers the specific information cipher key with the usual key to be outputted as the key message.
Thus, it becomes possible to distribute the specific information cipher key to the destination information reception device prescribed by the ITU-T G.983 or the like.
(16) Also, in the above-mentioned present invention (14), the key message processor may receive the key message as a vendor specific message of a PLOAM cell, and may decipher a message field thereof with the usual key.
Namely, the key message processor deciphers with the usual key e.g. the specific information cipher key included in the message field of a vendor specific message in a received PLOAM cell.
Thus, it is possible for the destination information reception device prescribed by the ITU-T G.983 or the like to receive the specific information cipher key.
(17) Also, in the above-mentioned present invention (15), the usual key may comprise a churning key.
(18) Also, in the above-mentioned present invention (16), the usual key may comprise a churning key.
(19) Also, in the above-mentioned present invention (13), the cipher message generator may insert the specific information into a message field of a PLOAM cell, and may generate the cipher message ciphered with the specific information cipher key.
(20) Also, in the above-mentioned present invention (14), the cipher message processor may decipher a message field of a PLOAM cell received as the cipher message with the specific information cipher key.
(21) Also, in the above-mentioned present invention (15), the information transmission device may further comprise: a setting message generator for generating a setting message including at least any one of cipher setting information indicating whether or not the specific information is set to be ciphered with the specific information cipher key, broadcast setting information indicating whether or not the cipher message should be transmitted by broadcasting, and header mask setting information for designating a specific user cell; and a churn processor for transmitting the specific information inserted into a payload field of a user cell designated by the header mask setting information in forms indicated by the cipher setting information and the broadcast setting information.
Namely, the setting message generator generates a setting message including any one of the cipher setting information indicating whether or not the specific information is ciphered with the specific information cipher key, the broadcast setting information indicating whether or not the cipher message including the specific information is transmitted by broadcasting, and the header mask setting information designating a specific user cell.
The message transmitter transmits the setting message, and notifies to the information reception device a presence/absence of ciphering, a form of a communication, and a designation of a user cell.
Thereafter, the churn processor transmits, in the form indicated by the cipher setting information and the broadcast setting information, the specific information inserted into a payload field of a user cell designated by the header mask setting (header setting and mask setting thereof).
Thus, it becomes possible to transmit a specific user cell in text ciphered with the specific information cipher key or in plain text by unicasting or broadcasting.
(22) Also, in the above-mentioned present invention (16), the information reception device may further comprise: a setting message processor for storing at least any one of cipher setting information included in a setting message received from the source information transmission device and indicating whether or not the specific information is set to be ciphered with the specific information cipher key, broadcast setting information indicating whether or not the cipher message should be transmitted by broadcasting, and header mask setting information for designating a specific user cell; and a dechurn processor for receiving the specific information inserted into a payload field of a user cell designated by the header mask setting information in forms indicated by the cipher setting information and the broadcast setting information.
Namely, the setting message processor receives cipher setting information indicating whether or not the specific information is set to be ciphered with the specific information cipher key, broadcast setting information indicating whether or not the cipher message is transmitted by broadcasting, and header mask setting information for designating a specific user cell, and stores the information.
The dechurn processor receives a user cell designated by the header mask setting information by unicasting or broadcasting indicated by the broadcast setting information, so that the specific information inserted into the payload field of this user cell is extracted in a form indicated by the cipher setting information in deciphered text or in plain text.
Thus, it becomes possible to receive a specific user cell in plain text or ciphered with the specific information cipher key by unicasting or broadcasting.
(23) Also, in the above-mentioned present invention (13), the setting message generator may generate at least any one of cipher setting information, broadcast setting information, header setting information, and group setting information in a message field of a PLOAM cell.
(24) Also, in the above-mentioned present invention (14), the setting message processor may receive at least any one of cipher setting information, broadcast setting information, header setting information, and group setting information included in a message field of a PLOAM cell.